Pausanias classifies the fortifications of the ancient city among the most excellent and compares them to the walls of Messene, Byzantium and Rhodes. According to the traveler the walls were built with the assistance of the Thebans, who wanted to create a strong base for controlling the Antikyra Gulf, in view of the encounter with Philip II. However, the Thebans and their allies, among which the Ambrysseis were defeated at Chaeronea (338 BC).

The ancient city was divided into three sections, the acropolis, the asty (city) and the open the countryside (fields and cemeteries). The citadel and the asty had strong fortifications with towers, built in the trapezoidal masonry, which was gradually expanded with additional weaker defenses.